Osg 1651504908 Spiral Point Tap 7/8-9 Unc V Coated

Product Description

The OSG 1651504908 is a spiral point tap designed for threading 7/8-9 UNC holes in production and job-shop environments. Built from powdered metal high-speed steel (PMT15 grade) with a V coating, this tap delivers consistent thread quality in a wide range of ferrous and non-ferrous materials. The plug chamfer distributes cutting load across the lead threads, making it well suited for through-hole applications. With a 3-flute spiral point design, chips are pushed forward ahead of the tap, reducing clogging and enabling higher feed rates. Overall length is 5.512 inches and thread length is 1.334 inches, fitting standard tap holders designed for 7/8-inch shank tooling.

This tap is intended for use on manual and CNC machining centers, drill presses, and tapping machines where 7/8-9 UNC internal threads are required. It produces Class 3B fit threads, appropriate for close-tolerance fastener assemblies. Material application range includes low-carbon steel, medium-carbon steel, high-carbon steel, alloy steel, die steel, hardened steel, cast iron, stainless steel, aluminum, and cast aluminum. Series 16515 positions this tap as a high-performance tool for shops requiring reliable threading across mixed-material workloads.

Key Features

• 7/8-9 UNC thread form with Class 3B fit tolerance
• Powdered metal HSS (PMT15) construction for improved wear resistance over conventional HSS
• V coating reduces friction and extends tool life in ferrous and stainless materials
• 3-flute spiral point pushes chips forward, ideal for through-hole threading
• Plug chamfer for standard through-hole entry and balanced cutting forces
• Right-hand thread direction, H4 thread limit, non-coolant-through design

Compatibility

Designed for use with standard tap holders and chucks accepting a 0.987-inch shank diameter. Suitable for through-hole tapping applications requiring 7/8-9 UNC Class 3B threads across the listed material types.

Installation Notes

This tap should be installed by a machinist or tooling technician familiar with CNC or manual tapping operations. Ensure the spindle is fully stopped and the machine is in a safe state before changing tooling. Use an appropriate cutting fluid or tapping compound for the workpiece material, particularly when working with stainless steel or hardened steel. Follow the machine manufacturer's recommended feed and speed parameters for the tap diameter and material combination.